Safety hoist brake



B. v. E. NORDBE RG SAFETY HOIST BRAKE Jan. 19, 1932.

.Filed May 25, 1929 2 Sheets-Sheet 1 Jan. 19, 1932. a. v. E. NORDBERG SAFETY HOI ST BRAKE Filed May 25, 1929 2 Sheets-Sheet 2 Patented JamiiS, 1932 TATEsf-PA-TEN oFFI BRUNO v. n. ivonnnnae, or, ILWAU E, WISCONSIN, AssIGNoRmo ivonnarzne mae- L racrvnme COMPANY, OEMILWAUKEE, Wisconsin, e-conroaar oiv or WISCONSIN M y Application fi led m y 25,

The present invention relates: to power brakes for elevators and minehoists and more particularly to mechanism for controlling the j brake under abnormalzor emergency conditions. Brake operators" for hoists of the type 1 the power lines. Automatic brake application may occur at a time when the cage is between levels and, particularly'in case of fire, it is often desirable to release the brakes to permit further descent or elevation to bring the cage to a level at whichtheioccu- I pantscan leave the cage. The presentinvention has for oneof its objects the provi sion of a mechanism for releasing the automatic brake operator and returning the brakes to normal control.

It is another object of the invention so to arrange the automatic operator that, so long as abnormal conditions exist, it again applies the brakes immediately upon release of the manual con:

trol. Further objects will be apparent from the following descriptionof a preferredemv 7 comprises the. poppet valves- 31,? 32,1 cooper- 'lating with seats 33, 34, the valve headsbein I "formedson -plungers .35 ,i36. l.Each of thei plungersg'35, 36 ispivoted to a lever; 37fb1lt to Epermitinecess'ary"relative movement' between bodiment of the invention and the accoma panying drawings in which: a v Fig.- 1 is a -side elevationof the brake and i mechanism for applying the brake; and

Fig. 2 is an enlarged fragmentary view of aportion of Fig. 1. V 1;;7 i The brake applying mechanismillustrated in the drawings is aowell known form in which a' drum 11, on which the cable sup porting the cage is wound, hasaperipheral braking surface withwhiclr the shoes 12,.

having facings 13, are "adapted to coact for the purpose of preventing rotation of the drum. The shoesi12 are supported by links 14 fixed to base members .15 and are connected by adjustablelinks'ld- Bell cranks 17 are connected to the shoes 12 and links-16 in the usual'mann'erso that when the bell cranks are drawn toward each ,otherthe shoes engage the drum. A lever 18 ;is fulcrumed at 1 19 to one of thebrake shoes and links: 20

connect the bell cranklevers j17. with "the lever 18. Supported onthe lever 18 at'some distance from its fulcrum-19is a weight 121 1 6 9; iseriai nonsense l y held an elevated position a piston in cylinder 22, a connecting rod 23; v

connecting the piston wit-hythe end oflever pressure on "the when the weight21 descends;

The mechanism fonmanually controllingthepositiOn of'the brake shoesflincludes a Edouble valve 25 designed tocontrol theflow of fluid to and from cylinder 22, thus raising or lowering. the-piston and weight 21. The

valve 25 comprises a housing 26 having 'a port 27in-communication. with fluid under pressure anda discharge port 28.,iInf 'tlie 2 present instance the fluid-employed is oil',-; an I accumulator :pfovidingthe source of pre's sure to whichLport 27 issconnected while port 7 28leads to a sump for the dischargedoil-n It will be seen from the drawings that? passage 7 i i 29 communicating'withfcylinder 22 maybe connected with either. of the ports 28,; or,

The means! for opening the :"por-ts 27 28 1 the lever and-plunger 3 5, a: 'pin andslot COIL-1, nection 38' is provided. Spring 39 is' connected to the valve housing25'and tolever 37 midway between plungers 35 and 36a nor-f 'mally: to holdboth -valves againsttheir seats, I e

in which position the passage 29 is cut off from ports'27, 28 When the lever.37 is port 28 to the passage 29 and cylinder 22. This permits the oil in cylinder 22 to flow to the sump, the weight 21 then descending and drawing the brake shoes into engagement with the drum.- V

' Pivotally secured to the lever 37 is a latch member 40 provided with a slot 41 adapted to engage pin 42 on lever 43, the latter being pivoted at 44 to the valve housing 26. The latch is normally urged into engagement with pin 42 by a spring 45 one end of which is attached to lever 37 while the other end thereof is secured to the latch member. Lever 43 is connected through-link46 with one endof a floating lever 47 the other end ,of whichisconnected to weight 21. "Guide link 48 is connected at its ends with the I weightand one. of the links 14' respectively.

Fulcrumed in bearing 49 is a lever 51 one end of which is connected by meansof a link 52 with .fioatin'glever 47, the other end of'the lever being: connected'to the handoperated which responds to ioverspeed, overwinding", "em, and which may beof anyofthe well brake.

lever 53 through link 54 andarm 55. It will thus be seen that movement of the :lever 53 t'o'the right'will raise .lever37. through link 46,, lever 43 and latch member 40, opening valve .31 and permitting 'oil under pressure to flowinto cylinder; 22 so as to raise weight 21. In this position of thelever the'brakeis released. Bymoving lever 53 to the left lever 37 i's'lowered, valve 32'opened and oil discharged from the'cylinder .to apply the After the hand 'lever 53 has beenmoved either to release or apply the brake and maintained in'a desired position, the link52 isrelatively stationary and acts as a fulcrum for floating lever -47. If the weight 21 is being lowered, for instance, so long as link 52 is stationary the link 46 and levers 43 and 37 will be raised. This will return the valves 31 and 32 to closed or lapped position whereupon further downward movement of the weight '21 will cease. The converse is true during I elevationjofthe weightfthe valves 31 and 32 alwaystending to return tolapped position during movement of the weight. f p v The automatic means 1 for applying the brake are responsive either to a device56 known types employed for thispurposes, or to a solenoid controlled mechanism which depends on the existence of electric energy in;tlie system. One formof governor 56 is shown in Fig. 1, in; which a disc 81 is provided with camsf82, '83, correspondingrespectively with the upper and lower limits of .cage travel: The disc makes one complete frevolution when the cage travels either, from itsuppermost to its lowermost level. or vice versa, and th'e L'cams cooperate with switch :arm- 84, pivoted at 85, to rock the arm. At

ends'ofarm84 are contacts 86, 87, adap break the solenoid circuit.

' that the circuit will be broken when either of the cams 82, 83, rocks switch arm 84, thereby deenergizing solenoid 57. The circuit 88 may also be broken by a speed responsive mechanism comprising-a fly-ball governor 91 having a ring 92 bridging contacts 93, 94. At a predetermined speed of the cage, ring 92 is elevated to clear contacts 93', 94, therebyto The solonoid' is also deenergized if, for any reason, the wires thereof'are broken or disrupted. The brake is applied when, under any of the conditions referred to, the circuit is broken, resulting in deenergization of the solenoid 57, the armature of which, is attached to a weight 58 and cooperates with'rod 59. The latch member 40 described-above'is further provided with an arm ortail 61 extending at right angles thereto. xR-od'59 is provided at its upper end with a pin adapted to engagethe tail 61. So long as the power system is supplied with current the solenoid will be energized and weight 58 maintained in'an elevated position without interfering with the normal manual operation of the control valves. Should the power be cut oil for any reason, such as fire, broken lines, etc., the solenoid will be deenergized, whereupon the weight 58 will drop, depressing the tail 61 and releasing latch member 40. The rod 59 not only clepresses the tail 61 but lowers lever 37 so that the outlet valve 32 will be opened to" discharge oilfrom cylinder 22. In this manner, upon deenerglzatlon of the solenoid, the

weight 21 is permitted to fall and the brake is instantly applied. It is to be noted that, since the latch 40 is disengaged from lever 43, the floating lever 47 has no connection with lever. 37 and will not return the valves to lapped position. The brake will therefore remain in applied relation to the hoist drum so long as the'weight 58 is in its lowest position.

As stated above, deenergization of the solenoid may'occur at time whenthe cage is between two levels, in which case it is apparent that the occupants of the cage will be in extreme danger should fire, smoke or gas enter the hoist shaft. Under such circumstances it is desirable that the hoist operator regain manual control of the brake mechanism. Means for lifting weight 58 and reengaging the latch device are therefore provided.

66 of lever. 67. The other arm 68 of lever 67 ispivotally connected to a foot treadle 69 positioned adjacent lever 53 on the oper'ators platform 71. When 'it' is desired to regain manual control of the-valve operating mechanism controlling movement of weight 21 the treadle 69 is depressed whereupon the cam 62 will swing upwardly and elevate the weight 58. The connecting rod 59 is likewise raised releasing tail 61 and 'lever 37. Spring-45 will urge latch member into engagement with pin42 on lever 43 and when the rod 59 has been raised a sufficient amount latch 40, wiliagain engage pin 42. It will therefore be seen that by depressingtreadle 69 and maintaining weight 58 in an elevated position it is possible to manipulate lever 53 and manually operate the power brake. Im-

mediately upon release of the treadle, however, it is apparent that weight '58 will drop and disengage the valve operating levers associated with the manually controlled lever 53. a a a v j -While the particular arrangement de-' scribed above is preferred form .of the .1nvention it is obvious that the details maybe modified as desired and the mechanismgap plied to other types of'brakes.

What is claimed is:

1. The combination of a rotary drum ;'brak ingmeans'therefor; a manual control for. said braking means; automatic means responsive to abnormal conditions for applying said braking means; means actuated by said autoautomatic means responsive to abnormal con '7 diti'ons for releasing said connection said applying, means being 'operab'leto brake said drumupon release of said connection; manually operable'means for resetting the con: nection to permit release :ofthe braking means; said applying means being returned: r

to braking position upon release of said manually operable means. i C l 5. The combination of 1a; rotary drum;

brake applying means therefor ;fluid operat ed means for actuating said applyingmeans;

a manual control for said fluid operated means; a releasable connection between said u a fluid-@operatedmeans and said; control; electrically operated means adapted when energizedto permit the fluid operated means to be connectedtosaid control andwhendeenergizedto releasesald connection; and ma'nually operated means for restoring said: 0011- necti'onwhile. said electrically operated means" a is deener'gizedf 1 v whereof I have signedmy i In testimony name to' this specification.

c rs wnov. E}. NORDBERG.

matic means for placing saidmanul control Y 7 sponsive to abnormal conditions for apply:

ing said braking means said automatic means i jiooi being adapted to disconnect said braking means from said manual control under said abnormal conditions; and manually operable means for restoring said automatic means to normal position to permit manualcontrol of said braking ditions exist. 7

, 8. The combination of a rotary drum; pow:

means while said abnormal coner braking means therefor; a manualcontrol j for said braking means; automatic means re 1 sponsive to'abnormal conditions for applying said braking means; said automatic means being adapted to disconnectsald braking means from said manual control under'said abnormal conditions; and manually operable means for reestablishing the connection be-. tween said manual control and said braking means to permit manualcontrol of the braking means; said automatic means being adapted to break said connection upon release of said manually operable means so long-as said i V a abnormal conditions exist. p l

a. The comb nat on of a rotary drum; brakingmeans therefor; means for applying said braking means; a manual controlifor said applying means; a releasable connection be tween said control and said applying means; 

